1. Field of the Invention
This invention relates to electric guitars and, more particularly, to narrow hollow body guitars having magnetic and crystal pickups.
2. Description of the Prior Art
There are generally three types of guitars in standard usage. The first type is the traditional large body acoustic guitar which has been used for many, many years. In acoustic guitars, all of the musical energy from the vibrating strings is utilized to move air. The top, bottom, and sides of the guitar are relatively thin and are relatively flexible so that the resonant chamber beneath the strings vibrates when a note is played on a string of the guitar. When a note is fretted and then unfretted by lifting a fret hand finger, the resonant chamber continues to vibrate even though the string vibration stops.
The acoustic chamber is sensitive to the vibration from strings, and is particularly sensitive to a number of individual notes played in quick succession. The air in the acoustic chamber vibrates in response to the vibration of a new note while it is still vibrating to preceding notes.
The resonant chamber of the large body acoustic guitars is also sensitive to external air-moving devices, such as loud speakers. This results in feedback problems very well known to anyone who tries to amplify acoustic instruments.
A second type of acoustic guitar is the semi-hollow body electric guitar, with F-hole ports or sound holes. The body is narrower than traditional, large body guitars, and the body has much less volume than the traditional large body acoustic guitar. It therefore relies on magnetic pickups to produce sound.
The third type of guitar is the solid body electric guitar, which is typically not concerned with the movement of air or with sound chambers. Rather, solid body electric guitars typically utilize magnetic pickups for sound reproduction from steel strings. The output from pickups is amplified and transmitted through speakers.
U.S. Pat. No. 3,454,702 (Elbrecht et al) discloses electrical circuitry for controlling the tone and for blending the output from electromagnetic and crystal pickups. The '702 patent uses a dual channel amplification system, in which the outputs from the two pickup circuits are connected together in parallel. The patent is not concerned with guitar structure, but merely with the electronics involved in the pickup system utilizing two pickups, an electromagnetic pickup and a crystal pickup.
U.S. Pat. No. 3,769,871 (Cawthorn) discloses a stone guitar with a tuned neck. The body of the guitar is made of stone. The guitar structure is that of a solid body guitar simply made out of stone. Electronic elements involved in the guitar apparatus of the Cawthorn patent are disposed in the stone body.
U.S. Pat. No 4,491,051 (Barcus) discloses a pickup system utilizing a piezoelectric transducer mounted in the bridge of an acoustic guitar or on string adjusters of a solid body guitar. The piezoelectric apparatus, while disposed within the bridge, is also in direct contact with the top plate of the guitar. The pickup thus extends through the bridge. The saddle for the strings is disposed directly on top of the pickup and accordingly extends into the bridge and is virtually free floating on the piezoelectric pickup apparatus.
U.S. Pat. No. 4,501,186 (Ikuma) discloses a particular pickup device for an acoustic guitar. The pickup utilizes both a magnetic pickup disposed in the sound hole of a guitar and piezoelectric pickup detachably attached in the sound hole of the guitar.
UK Patent 2,137,007 A discloses an electric guitar which has a rigid back and side walls and a flexible top plate. A transducer is mounted to the underside of the top plate. The guitar apparatus may be used either as a conventional electric guitar or as an acoustic guitar both with and without electrical amplification.
The inventor herein has developed a narrow hollow body electric guitar without a sound hole or port in which string vibrations are sensed by magnetic pickups and by crystal pickups and the entire sound chamber is used in conjunction with the crystal pickup. The sides and bottom of the sound chamber are relatively thick so that the wood out of which the body of the guitar is made does not vibrate, or vibrates only a minimum amount. Rather, the acoustic energy of the sound chamber is focused in a location adjacent to the crystal pickup. The basic guitar design of the narrow hollow body guitar is described and claimed in copending application Ser. No. 827,520, filed Feb. 10, 1986, which ultimately matured, through a continuation-in-part application, into Pat. No. 4,741,238, issued May 3, 1988, by the inventor herein.
If the acoustic energy of guitars causes the top, bottom and sides of the sound chamber to vibrate, it follows that the sound chamber will also be responsive to vibrations originating outside of the guitar, such as from external moving devices such as loud speakers. The resultant feedback problems are known and understood by those who have tried to amplify acoustic guitars.
The apparatus of the present invention overcomes the problems of the prior art by utilizing a crystal pickup under the saddle on a bridge of a guitar, with the bridge and saddle being disposed at the acoustic center of the sound chamber in a narrow hollow body guitar without sound holes or ports. When combined with the magnetic pickup, the crystal pickup fills in all of the musical tones and harmonics missing in guiters utilizing only magnetic pickups. The combination of crystal pickup and magnetic pickup produces a sound which is referred to as an "eloustic" sound. The eloustic sound makes the standard magnetic pickup electric sound more pleasing to the ear in a musical sense. Moreover, the musical output from the crystal pickup fills in the musical tones and harmonics that are generally not brought out in common electric guitars using only magnetic pickups. Thus, the electric guitar of the present invention provides a relatively complete musical instrument with a subtle combination of electric and acoustic properties that provide a sound different from the sounds produced by guitars of the prior art.